What is the Ecological Footprint?
The Ecological Footprint is a resource accounting tool that measures how much biologically productive land and sea is used by a given population or activity, and compares this to how much land and sea is available. Productive land and sea areas support human demands for food, fiber, timber, energy, and space for infrastructure. These areas also absorb the waste products from the human economy. The Ecological Footprint measures the sum of these areas, wherever they physically occur on the planet. The Ecological Footprint is used widely as a management and communication tool by governments, businesses, educational institutions, and non-governmental organizations.

What does the Ecological Footprint measure?
Ecological Footprint accounts answer a specific research question: how much of the biological capacity of the planet is demanded by a given human activity or population? To answer this question, the Ecological Footprint measures the amount of biologically productive land and water area an individual, a city, a country, a region, or all of humanity uses to produce the resources it consumes and to absorb the waste it generates with today’s technology and resource management practices. This demand on the biosphere can be compared to biocapacity, a measure of the amount of biologically productive land and water available for human use. Biologically productive land includes areas such as cropland, forest, and fishing grounds, and excludes deserts, glaciers, and the open ocean.

Global hectares are hectares with world-average productivity for all productive land and water areas in a given year. Studies that are compliant with current Ecological Footprint Standards use global hectares as a measurement unit. This makes Ecological Footprint results globally comparable, just as financial assessments use one currency, such as dollars or Euros, to compare transactions and financial flows throughout the world.

How accurate are Ecological Footprint measurements?
Current Ecological Footprint accounts provide a robust, aggregate estimate of human demand on the biosphere as compared to the biosphere’s productive capacity. As with any calculation system, Footprint accounts are subject to uncertainty in source data, calculation parameters, and methodological decisions. Several organizations are seeking to allocate resources towards obtaining more accurate estimates of this nature.

What can Ecological Footprint Analysis tell us about the future of the planet? Are we all doomed?
The Ecological Footprint highlights the reality of ecological scarcity, which can be disconcerting and frightening information. The existence of global overshoot suggests that human society will need to make significant changes to ‘business as usual’ if it wants to create a sustainable future. Robust and accurate Ecological Footprint accounts can help us make decisions towards sustainability, and can quantitatively show the positive impacts of groups, businesses, and people making decisions that are helping to bring human demand within the means of the planet.

What is the proper way to use the term Ecological Footprint?
The term Ecological Footprint, capitalized, is a proper name referring to a specific research question: how much of the biological capacity of the planet is demanded by a given human activity or population? Often, the word ‘footprint’ is used generically to refer to human impact on the planet, or to a different research question. As commonly used today, for example, the term ‘carbon footprint’ often refers to the number of tons of carbon emitted by a given person or business during a year, or to the tons of carbon emitted in the manufacture and transport of a product. In Ecological Footprint accounts, the ‘carbon Footprint’ measures the amount of biological capacity, in global hectares, demanded by human emissions of fossil carbon dioxide. The term Ecological Footprint has been deliberately excluded from trademark to encourage its widespread use.

How is an Ecological Footprint calculated?
Ecological Footprints can be calculated for individual people, groups of people (such as a nation), and activities (such as manufacturing a product).

The Ecological Footprint of a person is calculated by considering all of the biological materials consumed, and all of the biological wastes generated, by that person in a given year. These materials and wastes each demand ecologically productive areas, such as cropland to grow potatoes, or forest to sequester fossil carbon dioxide emissions. All of these materials and wastes are then individually translated into an equivalent number of global hectares.

To accomplish this, an amount of material consumed by that person (tons per year) is divided by the yield of the specific land or sea area (annual tons per hectare) from which it was harvested, or where its waste material was absorbed. The number of hectares that result from this calculation are then converted to global hectares using yield and equivalence factors. The sum of the global hectares needed to support the resource consumption and waste generation of the person gives that person’s total Ecological Footprint.

How does the Ecological Footprint address waste flows?
From an Ecological Footprint perspective, the term ‘waste’ includes three different categories of materials, and each category is treated differently within Footprint accounts.

First, biological wastes such as residues of crop products, trimmings from harvested trees, and carbon dioxide emitted from fuel wood or fossil fuel combustion are all included within Ecological Footprint accounts. A cow grazing on one hectare of pasture has a Footprint of one hectare for both creating its biological food products and absorbing its biological waste products. This single hectare provides both services, thus counting the Footprint of the cow twice (once for material production and once for waste absorption) results in double counting the actual area necessary to support the cow. The Footprint associated with the absorption of all biological materials that are harvested is thus already counted in the Footprint of those materials.
Second, waste also refers to the material specifically sent to landfills. If these landfills occupy formerly biologically productive area, then the Footprint of this landfill waste can be calculated as the area used for its long term storage.

Finally, waste can also refer to toxics and pollutants released from the human economy that cannot in any way be absorbed or broken down by biological processes, such as many types of plastics. Assessments of the Footprint of toxics and pollutants, when completed, generally refer to the Footprint of extracting, p
rocessing, and handling these materials, but not to the Footprint of creating or absorbing these materials themselves.

How does the Ecological Footprint account for recycling?
As the Ecological Footprint reflects the demand for productive area to make resources and absorb wastes, recycling can lower the Ecological Footprint by offsetting the extraction of virgin products, and reducing the area necessary for absorbing wastes. Recycling paper, for example, can decrease the total amount of virgin timber that must be harvested to meet global demand for paper, thus reducing humanity’s total Ecological Footprint.

The savings that result from the recycling process can be allocated to the person who recycles a material and/or the person who buys recycled material in a number of different ways:

100% to the person who buys the recycled paper (the wood fiber in a 100% recycled ream of paper could have no forest Footprint, since the footprint of that wood fiber was already allocated to the person who bought the virgin paper),

100% to the person who recycles the paper (a person purchasing 100% virgin paper who recycled all of it would have no Footprint for the wood fiber in that paper, since all of it is reused later, assuming that no fiber is lost in the recycling process), or

Split between the person who buys recycled paper and the person who recycles paper (the savings can be split 50%/50%, or in any other allocation).

Different researchers use different allocation principles for the savings from recycling, and standards-compliant Footprint studies will state their chosen allocation method explicitly. Regardless of allocation method, however, the largest reductions in Ecological Footprint can most commonly be achieved by reducing the total amount of materials consumed, rather than attempting to recycle them afterwards.